Bushmaster XM15 stuck cartridges

[Slamfire]

And, does a cartridge gauge provide some sort of length AND outside diameter check

Without gages, all your questions could be yes, no and maybe.

However the last one, quoted above, a typical cartridge headspace gage measures length only. The Wilson gages are cut "fat" between the shoulder and the base.

I wanted a gage that was exactly the same as my CLE chamber. So I paid Frank White of Compass Lake to cut me a cartridge gage with the same reamer that cut my chamber. Now I have something that will measure length and width. Cost about $40.00.

 

[xsquidgator]

Looks like I waited just a little too long to revisit this and my original thread disappeared, so please bear with me.

The gist of my problem is that when reloading .223 rounds for my 5.56x45, 1/9, 16" HBAR Bushmaster carbine, some cartridges seem to get stuck in the chamber before firing. I discovered this by accident when for some reason I stopped shooting a string before the mag was empty, and the bolt was stuck TIGHT when I tried to work the charging handle to eject the unfired case.

I posted this a week or two ago and got several thoughtful suggestions. The main suspect as I recall was possibly that I could be somehow partially collapsing the case shoulder during resizing or seating/crimping, which could make the outer diameter of the case be a little larger than it should be. A second possibility was that maybe I wasn't going all the way down to the cartridge base when resizing, and that maybe the base of the cartridge was oversize as a result.

I will hopefully get a chance today to test the second idea out, as I made another batch of rounds and made darned sure to go ALL THE WAY DOWN when resizing these. I have another batch of reloads I'd made where I didn't pay special attention to this detail, so I'm going to try both and see if I can duplicate the problem. (Both lots of reloads are using the same "R-P 223" brass)

My question today is, if the first problem, an oversized shoulder, is the case, what would you do to try to fix it? I use all Lee dies, and as I do with all my rifle reloads, I use 3 Lee dies (sizing/decapping, seating, and factory crimp die). I don't think my bullet seating operation is the culprit, as all it does is to seat the bullet. I like to put a decent crimp on my cases with the FCD, is there any possibility that the FCD is putting too much downward force on the case shoulder?

I measured the shoulders of some of my cases with calipers and compared them to some Remington 223 store-bought ammo I have. The shoulders on the commercial ammo seem to me to be about 0.350" whereas mine are about 0.352". It's hard to tell for sure because the measurement is made on the part of the case where it starts to taper off. The other thing that's kind of odd is, what IS the shoulder size supposed to be? I found the diagram below online, but it's a little different from the one in my Lee #2 guide. Lee says the shoulder should be 0.350" but this one below says 0.354".



Anyway, forgive the rambling, long story short is that I suspect that I may have a shoulder issue on my 223 reloads, perhaps somehow related to partially collapsing the shoulder at some point. Any suggestions on what I should do differently? I reload 3 other rifle calibers, do things the exact same way I do with these, and have never had this kind of problem. I'm curious as to what the peanut gallery might have to offer for advice.

 

[xsquidgator]

Ok, it's a dull subject. Just in the interests of completeness though, I think I've shed some light on the problem after a range-test session yesterday.
1) Ran 100 rounds of reloads using 223 brass (R-P if it matters), could not reproduce the stuck cartridge problem although I tried every combination I could think of, from cold chamber to rapid fire and then try to eject chambered round from a hot chamber. No problems whatsoever.
2) Then I ran maybe 5 rounds of misc brass reloads through the rifle, and got the stuck cartridge when chambering a Lake City headstamped reloaded 556 brass round.
3) Even when stuck, the technique of safe-ing the rifle and bumping the buttstock on something solid while pulling the charging handle, worked perfectly. Thanks for the tip!

So, I think I'll be careful about using 556 brass until I figure out more. But I have hundreds of range-pickup 223 I can use before I need to start using my range pickup 556 brass.

 

[HJ857]

You may also want to check the case length. The Lee case length gauge/zip trim combo is pretty efficient and guarantees a good length.

Anyway, just a thought. I recently had similar problems with a different AR caliber and it turned out to be overly long case length.

 

[xsquidgator]

You may also want to check the case length. The Lee case length gauge/zip trim combo is pretty efficient and guarantees a good length.

Anyway, just a thought. I recently had similar problems with a different AR caliber and it turned out to be overly long case length.

I'm pretty sure I'm good there - I use and like the Lee Zip trim and case length gauge/cutter. My trimmed cases are within 0.010" of what the Lee manual says they should be. I suspect a case diameter issue with the LC brass, perhaps it expands slightly after being sized unlike my 223 brass. Even if I don't end up fixing the root cause I'll be happy now 'cuz I know how to extract one of these stuck rounds if it happens again (buttstock tap while pulling charging handle).

 

[HJ857]

It certainly is an interesting problem. I've been using a good bit of LC and IMI range brass with Lee dies and have not had any issues. In fact, I have not been sorting brass at all, I have FC, R-P and Winchester and probably others mixed in there as well.

Just from a knowledge base aspect, I'm hoping for a definitive answer to your problem.